Large-dip-angle slate tunnel lateral triangular halfpace slotting row stripping type deep hole blasting method

Abstract

The invention discloses a large-dip-angle slate tunnel lateral triangular halfpace slotting row stripping type deep hole blasting method, relates to the technical field of slotting blasting methods, and aims to solve the problem that tunnel slate inclines leftwards at a large angle, triangular trapezoid straight hole slotting is adopted in the side direction of the whole section, explosive is intensively charged to hole bottoms, and the remaining blast holes are completely blocked by blast plugs and stemming. The hole bottom is fully broken, the slotting effect is guaranteed, the mode that slotting is formed in the lower middle portion of the tunnel in an inertia mode is changed, and the device can be applied and popularized in tunnels with similar stratums and geologies. The auxiliary blastholes are arranged in rows according to layered stratification, stratification stitches are avoided, stripping blasting of the row blastholes is achieved, drilling tool jamming is avoided during drilling, air tightness is achieved in the blasting process, the explosive energy utilization rate is increased, and the blasting effect is guaranteed. The deep locking feet are firmly welded with the arch frame, so that the problem that the primary support is damaged by large-dip-angle slate bias pressure is solved, reworking is avoided, the construction progress is totally accelerated, and the construction safety is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of slotting blasting methods, in particular to a slotting and stripping deep hole blasting method for a lateral triangular terrace in a large-angle slate tunnel. Background Art

[0002] In the prior art, when some tunnels are constructed using the two-step method, slot holes are arranged in the middle and lower part of the blasting section. Because the inclination angle is too large and the depth is too short, but it is necessary to pass through more than three layers of slate, and there is no sealing mud, a "baring teeth and cracked mouth" phenomenon occurs after the slot blasting. The slotting effect is very poor, resulting in poor blasting efficiency, a large number of large rocks, low ballasting efficiency, and even the need to handle large rocks separately, which is very time-consuming.

[0003] At the same time, due to the large inclination of the slotting eye, the gap between the slotting eye and the bottom of the first circle of auxiliary eyes is too large to be broken out, and there are many residual eyes, resulting in low penetration. The smooth blasting effect is too poor, and there is a "grin", which causes confusion in the initial support. The over-excavated part needs more slag and more concrete spraying, and the under-excavated part needs to be blasted again, which wastes time, causes material waste, delays in construction period, poor economic benefits, low wages for workers, and low enthusiasm, forming a vicious circle.

[0004] The right side of the inclined slate showed eccentric compression. 3 to 4 days after the initial support of the arch frame steel mesh sprayed concrete, the concrete cracked and fell off, the arch frame bent and deformed, and the initial support exceeded the limit, requiring reprocessing.

[0005] Therefore, blasting methods must be reformed and innovated. Summary of the invention

[0006] The purpose of the present invention is to provide a deep hole blasting method for lateral triangular terrace cutting and stripping of large-angle slate tunnels to solve the problems existing in the above-mentioned prior art and realize full-section deep hole blasting, which not only speeds up the construction progress, but also effectively controls the bias pressure to ensure construction safety.

[0007] To achieve the above object, the present invention provides the following solution: The present invention provides a deep hole blasting method for lateral triangular terrace cutting and stripping of a large-angle slate tunnel, comprising the following steps:

[0008] Step 1: Change the two-step blasting to a full-section one-step blasting excavation

[0009] On the basis of the original two-step blasting, after the arch frame is erected, the steel mesh is hung, and the concrete is sprayed on the upper step, the excavation is suspended; on the lower step, the blasting excavation is continued according to the original two-step blasting, and the arch frame is erected, the steel mesh is hung, and the initial support of the concrete is sprayed until it is flush with the upper step face;

[0010] Set up a total station, mark the elevation and tunnel centerline on the face, and take a triangular trapezoidal straight hole cut on the inclined side of the full section to account for the large angle inclination of the tunnel slate. Mark the positions of the triangular trapezoidal cut holes, auxiliary holes, peripheral holes, and bottom holes on the full section to form a surrounding rock excavation blasthole layout diagram;

[0011] Step 2: Use two-layer gantry to drill holes and charge

[0012] Move the two-layer excavation rig horizontally to the tunnel face, place it steadily and level it, place the repaired pneumatic drill, drill rod and drill bit on the tunnel face and the two-layer platform of the excavation rig according to the partition, connect the air duct and water pipeline; drill the blastholes according to the surrounding rock excavation blasthole layout diagram;

[0013] After drilling all the blastholes, the blast head is transported to the face and the stand. The groove holes, supplementary holes, auxiliary holes and bottom holes are all charged with forward continuous charge structure. The explosives are all loaded to the bottom of the blastholes. After a blast plug is pushed into the remaining blastholes, they are all sealed with blasting mud. The peripheral holes are charged to the bottom, and two sections of soft blasting mud are installed at the hole mouth to seal the hole mouth.

[0014] The large parallel blasting method is adopted for the whole section, and each blast hole is detonated to complete the blasting.

[0015] In one embodiment, in step 1, in the upper step of the original two-step blasting, the face is also sprayed with 50 mm thick concrete.

[0016] In one embodiment, in step 1, the positions of the triangular trapezoidal cut holes, auxiliary holes, peripheral holes, and bottom holes are marked with red paint on the entire cross section, and the hole positions should avoid the slate layer seams.

[0017] In one embodiment, in step 1, the spacing between the triangular trapezoidal cutout eyes, auxiliary eyes, peripheral eyes, and bottom eyes can be adjusted.

[0018] In one embodiment, in step 2, the depths of the groove holes, supplementary holes and bottom holes are 4.8 m, the depths of the auxiliary holes and peripheral holes are 4.5 m, and 149 blast holes are drilled in each cycle.

[0019] In one embodiment, in step 2, after all blast holes are drilled, the eye sweeper is connected to the high-pressure air duct to blow out all the water, debris, rock powder and mud in the blast holes and clean them up; at the same time, the pneumatic rock drill, drill rod and high-pressure rubber air belt are packed up and transported to a fixed storage location.

[0020] In one embodiment, in step 2, large parallel blasting is used for the entire section, ventilation is performed for 15 minutes after blasting, and an operator goes to the face to check the blasting situation.

[0021] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0022] The high-angle slate tunnel lateral triangular terrace slotting and stripping deep hole blasting method of the present invention adopts triangular trapezoidal straight-eye slotting on the full-section side in view of the large left-angle inclination of the tunnel slate, and densely charges to the bottom of the hole. The remaining blast holes are completely blocked with blast plugs and blast mud, so that the bottom of the hole is fully broken, ensuring the slotting effect, changing the inertial mode of arranging slots in the lower part of the tunnel, and can be promoted and applied in tunnels with similar strata and geology. The auxiliary blast holes are arranged in rows according to the layered bedding, avoiding the bedding seams, and realizing the stripping blasting. Not only does the drill not get stuck when drilling, but it is also airtight during the explosion process, which improves the energy utilization rate of the explosives and ensures the blasting effect. The deep locking feet are firmly welded to the arch frame to solve the problem of damage to the primary support caused by the bias pressure of the high-angle slate, avoid rework, and generally speed up the construction progress and ensure construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is the blasthole layout diagram of the lateral triangular terrace cutting and stripping deep hole blasting method for the high-angle slate tunnel. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a deep hole blasting method for lateral triangular terrace cutting and stripping of a large-angle slate tunnel, so as to solve the problems existing in the above-mentioned prior art and realize full-section deep hole blasting, which can not only speed up the construction progress, but also effectively control the bias pressure and ensure the construction safety. In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] like Figure 1 As shown, the present invention provides a lateral triangular terrace cutting and stripping deep hole blasting method for a large-angle slate tunnel, comprising the following steps:

[0028] Step 1: Change the two-step blasting to a full-section one-step blasting excavation

[0029] On the basis of the original two-step blasting, after the arch frame is erected, the steel mesh is hung, and the concrete is sprayed on the upper step, the excavation is suspended; on the lower step, the blasting excavation is continued according to the original two-step blasting, and the arch frame is erected, the steel mesh is hung, and the initial support of the concrete is sprayed until it is flush with the upper step face;

[0030] Set up a total station, mark the elevation and tunnel centerline on the face, and mark the positions of triangular trapezoidal cut holes, auxiliary holes, peripheral holes, and bottom holes on the entire section to form a surrounding rock excavation blasthole layout diagram;

[0031] Step 2: Use two-layer gantry to drill holes and charge

[0032] Move the two-layer excavation rig horizontally to the tunnel face, place it steadily and level it, place the repaired pneumatic drill, drill rod and drill bit on the tunnel face and the two-layer platform of the excavation rig according to the partition, connect the air duct and water pipeline; drill the blastholes according to the surrounding rock excavation blasthole layout diagram;

[0033] After drilling all the blastholes, the blast head is transported to the face and the stand. The groove holes, supplementary holes, auxiliary holes and bottom holes are all charged with forward continuous charge structure. The explosives are all loaded to the bottom of the blastholes. After a blast plug is pushed into the remaining blastholes, they are all sealed with blasting mud. The peripheral holes are charged to the bottom, and two sections of soft blasting mud are installed at the hole mouth to seal the hole mouth.

[0034] The large parallel blasting method is adopted for the whole section, and each blast hole is detonated to complete the blasting.

[0035] It should be noted that for the large-angle inclination of the tunnel slate, a triangular trapezoidal straight-eye cut is adopted on the inclined side of the full section. Only one circle of auxiliary eyes and one circle of peripheral eyes are left in the triangular trapezoidal cut area closest to the side (i.e. the inclined side). The triangular trapezoidal cuts are all straight eyes perpendicular to the face of the tunnel, with a side length of 500 to 800 mm. The harder the rock, the smaller the side length, and vice versa. After designing the blasting parameters according to theory and experience, the appropriate parameters can be determined after 2 to 4 blasts of practice.

[0036] Embodiment 1

[0037] Yuezhishan Tunnel is 14,085 meters long, with a single hole and double tracks. The entrance is connected to the roadbed, and the exit is connected to the double-track bridge. Except for a few turning curves, the rest are straight sections.

[0038] The tunnel geology is medium-layered slate, medium-thick to thick-layered metamorphic sandstone, with a small amount of layered phyllite, the layer thickness is generally 0.8-2.5m, the inclination angle is large, between 45° and 60°, the uniaxial compressive strength of the block rock is 40.5-91MPa, and the rock hardness coefficient f=4-9, which belongs to medium-hard rock. From the exposed strata, the slate layers are clear and regular, without seepage or gushing, but there is bias on the right side of the inclination, the primary support arch is severely deformed, and the shotcrete is cracked, peeled off, and intruded.

[0039] Original construction method

[0040] The tunnel was constructed using the two-step method. The upper step used a double-step wedge-shaped slotting method. The slotting angle was about 70°, which limited the slotting depth to less than 2.7m (otherwise, it was necessary to change to a short drill rod to drill 1.5m deep first, and then change to a long drill rod to continue drilling, which not only extended the time of this process, but also affected the drilling of adjacent drillers). The depth of the auxiliary holes and peripheral holes was 2.3-2.5m, and it was not used to block the blasting mud. The footage after blasting was not ideal. The rock block after blasting was 0.7-1.3m, with a maximum of 2.3m, which was not conducive to the side-unloading loader loading. The footage of each shot was generally 1.4-2.1m, and the monthly progress was 44-55m.

[0041] Therefore, in the more than three years since the tunnel construction began in the second half of 2016, the contracted construction period has exceeded 65%, the tunnel's comprehensive progress is only 4.8 kilometers, and the task completion is only 38%. The owner is very dissatisfied and requires the construction company to send an expert group to supervise and guide to ensure the realization of the contracted construction period.

[0042] The implementation steps of the lateral triangular terrace cutting and stripping deep hole blasting method of the high-inclination slate tunnel of the present invention are as follows:

[0043] (1) Changing the two-step blasting to full-section one-step blasting excavation

[0044] ① After the arch frame is erected, the steel mesh is hung, and the concrete is sprayed (the face must also be sprayed with 50mm thick concrete to ensure safety), excavation is suspended.

[0045] ② Continue blasting and excavation of the lower step according to the original plan, erect the arch frame, hang the steel mesh and spray concrete until it is flush with the heading surface of the upper step.

[0046] ③ Under the condition of ensuring safety, the survey personnel set up the total station, mark the elevation and tunnel centerline on the face, and use red paint to mark the positions of the triangular trapezoidal cut holes, auxiliary holes, peripheral holes, and bottom holes on the whole section according to the new blasthole layout diagram. Note that the hole position should avoid the slate layer seams, and the row spacing can be appropriately increased or reduced.

[0047] (2) Use two-layer gantry for drilling and charging

[0048] ① Move the two-layer excavation rig horizontally to the face, stabilize it and level it. Place the repaired YT-30 handheld air drill, 6.0m long hollow hexagonal steel drill rod, and φ38mm straight drill bit on the face and the two-layer platform of the excavation rig according to the partitions, and connect the air ducts and water pipes.

[0049] ② According to the layout of the blastholes for excavation of the surrounding rock, the area, personnel and number of holes shall be determined. In particular, experienced, skilled and accurate drillers shall be selected to drill the slot holes and peripheral holes. The angle, straightness, depth and spacing of the slots as well as the bottom of the holes shall be mastered, which is the key to the success of slot blasting. Figure 1 The depth of the groove holes, supplementary holes and bottom holes is 4.8m, the depth of the auxiliary holes and peripheral holes is 4.5m, and 149 blast holes are drilled in each cycle.

[0050] ③After drilling all the blast holes, connect the eye sweeper to the high-pressure air duct to blow out all the water, debris, rock powder, mud, etc. in the blast holes and clean them up. At the same time, pack up the pneumatic rock drill, drill rod, and high-pressure rubber air belt and transport them to a fixed storage location.

[0051] ④ The blasting heads made in a safe place are transported to the face and the stand. The groove holes, supplementary holes, auxiliary holes and bottom holes are all equipped with a forward continuous charging structure. The explosives are all loaded to the bottom of the blasting holes. After a blasting plug is pushed into the remaining blasting holes, they are all sealed with blasting mud. The peripheral holes are charged to the lower part, and 2 sections of soft blasting mud are installed at the hole mouth to seal the hole mouth.

[0052] ⑤ The whole section adopts large parallel blasting. Equipment and personnel are withdrawn outside the safety cordon. The squad leader issues the blasting order, and the blaster blasts according to the prescribed actions. Ventilate for 15 minutes after blasting. After confirming safety, the safety officer, blaster and squad leader go to the face to check the blasting situation. If no falling blast or blind blast is found, the warning can be lifted and the next construction process (mud removal) can be carried out. Otherwise, the blind blast plan should be followed to eliminate the danger.

[0053] (3) Blasting effect is significantly improved

[0054] ① Starting from October 1, 2018, the lateral triangular trapezoidal straight hole deep hole slotting and stripping blasting method was adopted. 149 blast holes were drilled in each cycle of the whole section. The depth of the slot hole and the bottom hole was 4.8m, and the depth of other blast holes was 4.5m. A total of 272.8Kg of explosives were loaded. The penetration of each shot was 3.4~4.3m, an average of 4.1m, and the average blast hole utilization rate reached 91%. The penetration of each shot was 2.0~2.4 times higher than the original 1.4~2.1m. Now there is an average of 1 shot per day, and the monthly progress is 102~129m, which is 2.3 times higher than the original 44~55m.

[0055] ② As the progress was accelerated to twice the original speed, and the 6.0m anchor pipe was used at the right side of the bias to firmly lock the arch frame, there was no arch frame deformation and limit violation rework phenomenon, which digested the delay in the early construction period. The tunnel was completed 15 days ahead of the contract period, creating good conditions for the timely laying of tracks on the entire line.

[0056] The key point of the present invention is to adopt a lateral triangular trapezoidal straight-eye cutting method for the layered slate with a large dip angle, arrange the auxiliary holes in parallel with the slate bedding, and seal the taphole mud to achieve effective deep hole blasting.

[0057] The advantages of the present invention are as follows:

[0058] ① In view of the large left-angle inclination of the tunnel slate, a triangular trapezoidal straight-hole cut was adopted for the first time in my country on the side of the whole section, and the charges were densely loaded to the bottom of the hole. The remaining blast holes were completely blocked with blast plugs and blast mud, so that the bottom of the hole was fully crushed and the cavity was blasted out as much as possible, creating good conditions for blasting other blast holes.

[0059] ② The auxiliary holes are also arranged in layers and avoid bedding joints. When blasting, it is like peeling off one row after another like opening a mountain on the ground, and the blasting effect is good.

[0060] ③ Based on the original arch frame (anchor pipe locking foot), steel mesh, shotcrete and other primary support parameters, the locking foot anchor pipe with a diameter of 42mm and a length of 3.5m was changed to a length of 6.0m. After installation, two U-shaped clips were used to weld the anchor pipe to the arch frame. The anchor pipe was then grouted with expansive cement mortar, which effectively resisted the damage of the biased primary support structure.

[0061] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0062] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A deep hole blasting method for lateral triangular terrace cutting and stripping of high-inclination slate tunnels, characterized in that: The following steps are involved: Step 1: Change the two-step blasting to a full-section one-step blasting excavation On the basis of the original two-step blasting, after the arch frame is erected, the steel mesh is hung, and the concrete is sprayed on the upper step, the excavation is suspended; on the lower step, the blasting excavation is continued according to the original two-step blasting, and the arch frame is erected, the steel mesh is hung, and the initial support of the concrete is sprayed until it is flush with the upper step face; Set up a total station, mark the elevation and tunnel centerline on the face, and take a triangular trapezoidal straight hole cut on the inclined side of the full section to account for the large angle inclination of the tunnel slate. Mark the positions of the triangular trapezoidal cut holes, auxiliary holes, peripheral holes, and bottom holes on the full section to form a surrounding rock excavation blasthole layout diagram; Step 2: Use two-layer gantry to drill holes and charge Move the two-layer excavation rig horizontally to the tunnel face, place it steadily and level it, place the repaired pneumatic drill, drill rod and drill bit on the tunnel face and the two-layer platform of the excavation rig according to the partition, connect the air duct and water pipeline; drill the blastholes according to the surrounding rock excavation blasthole layout diagram; After drilling all the blastholes, the blast head is transported to the face and the stand. The groove holes, supplementary holes, auxiliary holes and bottom holes are all charged with forward continuous charge structure. The explosives are all loaded to the bottom of the blastholes. After a blast plug is pushed into the remaining blastholes, they are all sealed with blasting mud. The peripheral holes are charged to the bottom, and two sections of soft blasting mud are installed at the hole mouth to seal the hole mouth. The large parallel blasting method is adopted for the whole section, and each blast hole is detonated to complete the blasting.

2. The method of deep hole blasting with lateral triangular terrace cutting and stripping in high-angle slate tunnel according to claim 1 is characterized by: In the step 1, in the upper step of the original two-step blasting, concrete with a thickness of 50 mm is also sprayed on the face.

3. The method for deep hole blasting of lateral triangular terrace cutting and stripping in high-angle slate tunnel according to claim 1 is characterized by: In the step 1, the positions of the triangular trapezoidal cut holes, auxiliary holes, peripheral holes and bottom holes are marked with red paint on the entire section, and the hole positions should avoid the slate layer seams.

4. The method for lateral triangular terrace cutting and stripping deep hole blasting of a high-angle slate tunnel according to claim 1 is characterized by: In the step 1, the row spacing of the triangular trapezoidal cutout eyes, auxiliary eyes, peripheral eyes, and bottom eyes can be adjusted.

5. The method of deep hole blasting with lateral triangular terrace cutting and stripping in high-angle slate tunnel according to claim 1 is characterized by: In the step 2, the depth of the groove hole, supplementary hole and bottom hole is 4.8m, the depth of the auxiliary hole and peripheral hole is 4.5m, and 149 blast holes are drilled in each cycle.

6. The method of deep hole blasting with lateral triangular terrace cutting and stripping in a high-inclination slate tunnel according to claim 1 is characterized by: In the step 2, after all the blast holes are drilled, the eye sweeper is connected to the high-pressure air duct to blow out all the water, debris, rock powder and mud in the blast holes and clean them up; at the same time, the pneumatic rock drill, drill rod and high-pressure rubber air belt are packed up and transported to a fixed storage location.

7. The method of deep hole blasting with lateral triangular terrace cutting and stripping in a high-angle slate tunnel according to claim 1 is characterized by: In the step 2, the whole section is blasted in large parallel, and ventilation is carried out for 15 minutes after blasting, and the operator goes to the face to check the blasting situation.

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